James Brown Scott played a key role in the growth of public international law in the United States from the 1890s to the 1940s. While little remembered today, he was well-known among his contemporaries as a leading spokesman for a new and important discipline. Scott rose from obscure middle-class origins to occupy a prominent and influential place as an international lawyer who shared his legal expertise with seven presidents and ten secretaries of state. By examining his life we gain insight into the establishment of public international law as a discipline and on the era when lawyers qua lawyers began to help shape American foreign policy.